Parting and grooving cutting inserts can be double-ended, with two opposing cutting edges located at the intersection of a top surface and opposing end surfaces of the cutting insert. In order that the non-active cutting edge does not limit the depth of cut during a cutting operation the two opposing cutting edges can be twisted with respect to each other so that said cutting edges are inclined in opposite directions. Examples of such cutting inserts are disclosed in, for example, U.S. Pat. No. 5,156,502, U.S. Pat. No. 5,975,812 and U.S. Pat. No. 8,647,028.
Alternatively, one of the cutting edges can be located at the intersection of a side surface and the end surface of the cutting insert. See, for example, EP 0150 901 A2, WO 2011/159119 and WO 2015/099369.
In addition, cutting inserts having a tetrahedral basic shape are known. Such cutting inserts are disclosed in, for example, U.S. Pat. No. 3,178,801, U.S. Pat. No. 3,981,057, U.S. Pat. No. 6,648,560 B2 and U.S. Pat. No. 8,459,907 B2.